Polyolefin materials having enhanced surface durability and methods of making the same by exposure to radiation

ABSTRACT

The invention relates to thermoplastic polyolefin compositions having enhanced surface durability and products thereof which include a thermoplastic polyolefin base component at least one radiation-crosslinkable component present in an amount sufficient to enhance the surface durability of the thermoplastic polyolefin component when radiation-cured and at least one photoinitiator present in an amount sufficient to initiate crosslinking of the radiation-crosslinkable component upon exposure of the thermoplastic polyolefin composition to radiation. The invention further relates to methods of providing a cured thermoplastic polyolefin composition having enhanced surface durability by preparing a mixture having a thermoplastic polyolefin base component, at least one radiation-crosslinkable component in an amount sufficient to enhance the surface durability of the polyolefin when radiation cured, and at least one photoinitiator each in an amount sufficient to facilitate crosslinking of the radiation-crosslinkable component when a surface of the thermoplastic polyolefin composition is exposed to radiation, and then exposing the thermoplastic polyolefin composition to radiation in an amount sufficient to crosslink the radiation-crosslinkable component thereby providing a thermoplastic polyolefin composition having enhanced surface durability.

This application is a division of application Ser. No. 09/732,731 filedDec. 11, 2000, now U.S. Pat No. 6,488,882, which is acontinuation-in-part of application Ser. No. 08/982,508, filed Dec. 2,1997, now abandoned.

TECHNICAL FIELD

This invention relates to thermoplastic, polyolefin materials(“polyolefins”) having superior mar, scratch, wear, and abrasionresistance and methods of making such polyolefins by exposure toradiation to crosslink unsaturated polyolefins therein.

BACKGROUND OF THE INVENTION

Polyolefins are useful in a wide variety of applications due to theirstrength, environmental resistance and moldability. Many polyolefins aretoo easily scratched, marred, worm, abraded or otherwise damaged ontheir surface. These surface characteristics may be measured in avariety of ways. For example, scratch resistance may be measured byvertically penetrating a scratch needle, with a spherical tip into apolyolefin or other material surface under a constant load. The needleis then moved horizontally at a constant rate, and the width and/ordepth of any formed scratch is measured (See, e.g., T. Nomura, et al.,J. Applied Polymer Sci. 55:1307-1315 (1995)). Generally, it has beendesired to enhance the service life of a polyolefin by improving thesesurface characteristics to reduce scratching, marring, wearing,abrasion, and the like.

One conventional method to enhance surface characteristics has been touse inorganic particulate material, such as various silicas. Uniformdispersion of these particulates is difficult to achieve, however, andthis results in non-uniform surface properties in such products. The useof these particulates also tends to damage other desirable physicalproperties of the polyolefin, resulting in loss of impact strength,toughness, processability, and the like.

A more effective conventional method of providing surface enhancingcharacteristics to certain polyolefins is disclosed in U.S. Pat. No.4,921,669. This patent discloses passing a web of extruded thermoplasticsynthetic resin through a polishing roll stack, wherein at least one ofthe rolls has thereon a film of a material forming such a scratchresistant coating that is transferred from the roll to the web surface.Such conventional methods of enhancing the surface characteristics of apolyolefin require expensive, bulky equipment that also increase theprocessing time of polyolefin products.

Another way to enhance surface characteristics of polyolefins isdescribed in U.S. Pat. No. 4,000,216, which discloses an extrudable,moldable, or heat formable blend of a thermoplastic polymer and asurface altering agent of at least one monoethylenically unsaturatedmonomer for said thermoplastic polymer, wherein the surface alteringagent has cross-linked polymer particles having an average size of 1 to30 m. The surface altering agent is preferably prepared by anendopolymerization, which is used with a compatible polyolefin to bealtered.

Another conventional way to enhance surface characteristics of variousarticles is to apply acrylic polymers or coatings to an article andsubsequently cure the polymer or coating with a radiation source, suchas ultraviolet radiation (“UV”). The following patents describe avariety of examples of such conventional “apply coating and cure”methods and compositions.

U.S. Pat. Nos. 4,153,526 and 4,039,720 disclose safety glass made bylaminating a saturated polyvinyl acetal film and a photoinitiator to aply of glass, and irradiating the film with UV to initiate crosslinkingand to provide improved solvent-abrasion resistance. U.S. Pat. No.4,227,979 discloses radiation-curable coating compositions including oneor more amide acrylate compounds that form mar-resistant protective anddecorative film coatings.

U.S. Pat. No. 4,255,303 discloses a composition for coating electricalapplications including ethylene polymer and at least 10 parts by weightof talc filler per 100 parts by weight of polymer, where the talc iscoated with at least one metallic salt of a fatty acid having 8 to 20carbon atoms. The ethylene polymers may be curable by irradiation withhigh-energy electron beams or a chemical curing agent, such as organicperoxide. U.S. Pat. No. 4,371,566 discloses actinic radiation curablecoating compositions for application to many substrates having apentaerythritol-based polyacrylate or polymethacrylate, such aspentaerythritol tetraacrylate, a vinyl chloride-vinyl acetate containingpolymer, and a photoinitiator, preferably applied by spraying a solutiononto the substrate.

U.S. Pat. No. 4,478,876 discloses a process of coating a solid substratewith an abrasion resistant silicone hard coating curable upon UVexposure under a non-inert atmosphere, such as air. The compositionincludes a UV crosslinkable polyfunctional acrylate monomer, SiO₂ in theform of colloidal silica, and acryloxy functional silanes and a selectedblend of ketone-type and hindered amine-type photoinitiators.

U.S. Pat. No. 4,814,207 discloses a method for applying a scratch andweather resistant film coating to a shaped article by applying to thearticle a thin film of a mixture of free radically polymerizable monomerhaving at least two polymerizable olefinic bonds, a peroxide initiatorhaving a half life of less than two minutes at 100° C., and anultraviolet stabilizer, and curing the film by heating it to atemperature greater than 70° C. U.S. Pat. No. 4,902,578 discloses aradiation-curable coating for thermoplastic substrates having apolyfunctional acrylic monomer, a mono-, di-, or trifunctional acrylicmonomer, a thermoplastic or elastomeric polymer, and a photoinitiator.

U.S. Pat. No. 5,006,436 discloses a UV curable, aqueous alkalinedevelopable solder mask composition having a thermal free radicalinitiator capable of generating free radicals with heat, and apolyunsaturated compound capable of being thermally crosslinked by thefree radicals to provide a substantially fully cured coating. U.S. Pat.No. 5,316,791 discloses a process for improving the impact resistance ofa coated plastic substrate by applying an aqueous polyurethanedispersion as a primer layer, partially curing the layer by air drying,applying a coating composition over the primer layer, and curing thecoating composition to form an abrasion-resistant hard coat. U.S. Pat.No. 5,382,604 discloses a crosslinked adhesive composition having anepoxidized diolefin block polymer crosslinked by UV radiation through atleast some of the epoxy functionality.

U.S. Pat. No. 5,558,911 discloses a method of coating articles withpowder coatings having polymers applied to the substrate to be coated,melting the polymers, and crosslinking by UV radiation.

U.S. Pat. No. 5,591,551 discloses a lithographic coating and method ofcoating at least a portion of a surface allow of an article with aradiation-crosslinkable polymer and exposing it to a pattern ofradiation to produce an image. The polymer is disclosed to be acopolymer of an isoolefin of 4-7 carbon atoms and para-alkylstyrene.

U.S. Pat. No. 5,618,586 discloses self-crosslinkable film-formingcompositions as coatings and a process for preparing multi-layeredcoated articles with a colored base coat and a clear top coat, whereinthe composition includes a non-gelled addition polymer that is the freeradical initiated reaction product of an N-alkoxymethyl(meth)acrylamideand at least one other ethylenically unsaturated monomer.

These conventional curable products generally require several steps,particularly coating or effectively laminating a prepared product withthe V-curable coating. However, it would be advantageous to provideindependent polyolefin compositions that are capable of being curedwithout the need for additional processing steps, such as coating orlaminating an article with a curable composition. It is thus desired toproduce such a product, preferably one having enhanced surfacedurability. The present invention provides new polyolefin compositionsthat satisfy this need.

SUMMARY OF THE INVENTION

The present invention relates to a thermoplastic polyolefin compositionhaving enhanced surface durability, which includes a base component of athermoplastic polyolefin, at least one radiation-crosslinkable componentpresent in an amount sufficient to enhance the surface durability of thethermoplastic polyolefin base component when radiation-cured, and atleast one photoinitiator present in an amount sufficient to initiatecrosslinking of the radiation-crosslinkable component upon exposure ofthe thermoplastic polyolefin composition to radiation.

In one embodiment, the polyolefin composition also includes a filler inan amount of between 0.1 to 30 weight percent. In a preferredembodiment, the filler includes calcium carbonate, clay, talc, mica,glass, zinc oxide, wollastonite, silica, titanium dioxide, or mixturesthereof.

In another embodiment, the thermoplastic polyolefin base component isthermally treated prior to or subsequent to radiation exposure. Thethermal treatment may vary in intensity from 25° C. to 150° C. and mayvary in duration from a few minutes up to a few days (e.g., from 2minutes to 48 hours) depending on the temperature and desired extent ofcure. Alternately, the base component can be subjected to a series ofalternating thermal and radiation treatments which may be of varyingduration lengths depending on the desired physical properties.

The compositions may contain photo-oxidative stabilizers that preventenvironmental degradation of the thermoplastic polyolefin base componentwithout interfering substantially with the photoinitiated surfacecrosslinking.

The thermoplastic polyolefin base component may include a blend of acrystalline or semicrystalline poly-α-olefin and an amorphouspoly-α-olefin. In a preferred embodiment, the thermoplastic polyolefinbase component includes a blend of semi-crystalline polypropylene andamorphous ethylene/α-olefin copolymer. In another embodiment, theamorphous poly-α-olefin includes amorphous copolymer of ethylene and atleast one diene. Generally, the thermoplastic polyolefin base componentis present in an amount of about 99 to 55 weight percent of thecomposition. In a preferred embodiment, the thermoplastic polyolefinbase component is present from about 95 to 65 weight percent of thecomposition.

The radiation-crosslinkable component may include an unsaturatedpolyolefin. In a preferred embodiment, the unsaturated polyolefinincludes an ethylene, propylene and diene terpolymer; polybutadiene;polyisoprene; a styrenic polymer; an ethylene and propylene copolymer;methacrylate grafted polybutadiene or mixtures thereof. Typically, theradiation-crosslinkable component is present in an amount of about 1 to30 weight percent of the thermoplastic polyolefin composition.

The photoinitiator may be any one of benzoin and benzoin etherderivatives; benzil ketal derivatives; α,α-dialkyoxyacetophenonederivatives; α-aminoalkylphenone derivatives; α-hydroxyalkylphenonederivatives; acylphosphine oxides; acylphosphine sulfides;phenylglyoxylate derivatives; O-acyl-2-oximino ketone derivatives;benzophenone and its derivatives; Michler's ketone and its derivatives;thioxanthone and its derivatives; mixtures thereof; and all thepolymer-bound compounds of the type mentioned above. In a preferredembodiment, the photoinitiator is benzil ketal derivatives; andacylphosphine oxides. The photoinitiator is typically present in anamount of about 0.01 to 5 weight percent of the composition. Mixtures ofphotoinitiators may also be used, along with accelerators thatfacilitate rapid crosslinking.

The invention also relates to a method of providing a curedthermoplastic polyolefin composition having enhanced surface durabilityby preparing a mixture of a thermoplastic polyolefin base component, atleast one radiation-crosslinkable component in an amount sufficient toenhance the surface durability of the thermoplastic polyolefin componentwhen radiation cured, and at least one photoinitiator in an amountsufficient to facilitate crosslinking of the radiation-crosslinkablecomponent when the thermoplastic polyolefin composition is exposed toradiation, and then exposing a surface of the thermoplastic polyolefincomposition to radiation in an amount sufficient to crosslink theradiation-crosslinkable component at least at the exposed surface,thereby providing a thermoplastic polyolefin composition having enhancedsurface durability.

In one embodiment, the radiation is selected to be ultraviolet, electronbeam, gamma, visible, microwave, infrared, or thermal radiation, ormixtures thereof. In another embodiment the radiation is imparted at apower of 0.1 J/cm² and above and at a wavelength between about 200 to500 nm.

In a preferred embodiment, the thermoplastic polyolefin base componentis selected to be a blend of a crystalline or semicrystallinepoly-α-olefin and an amorphous poly-α-olefin, theradiation-crosslinkable component is selected to be an unsaturatedpolyolefin that is present in about 0.01 to 20 weight percent of thecomposition, the photoinitiator is selected to be benzil ketals orphosphine oxides present in,;about 0.1 to 5 weight percent of thecomposition, and a filler is added to the mixture. The method mayfurther include forming the thermoplastic polyolefin composition into adesired shape prior to exposing the surface of the composition to theradiation.

The invention also relates to a thermoplastic polyolefin compositionhaving enhanced surface durability formed by the above-described method.In one embodiment, the composition has an outer surface that contains apolymerized component so that the surface scratch resistance afterirradiation has a rating of 1.5 or lower on the Solvay scale (seedefinition below) after cure.

DETAILED DESCRIPTION OF THE INVENTION

Polyolefin compositions having enhanced surface durability, and aprocess for making the same, have now been advantageously discovered.The polyolefin compositions of the present invention include athermoplastic polyolefin base component, a radiation-crosslinkablecomponent, and a photoinitiator, together with one or more optionalfillers used to create a final product having desired characteristics.The present invention is believed to influence the mechanics of surfacedeformation and recovery by preferentially introducing crosslinks nearthe surface of a formed article made from the polyolefin composition.Thus, the polyolefin compositions exhibit superior durability andresistance to marring, scratching, wear, abrasion, and other surfacedamage without the need for a cumbersome coating-type process.

The terms “thermoplastic polyolefin composition” or “polyolefincomposition” are intended to include any composition that contains oneor more crystalline or semicrystalline olefin polymers, such aspolyethylene, polypropylene or other C₅-C₂₀ olefins. The crystallinityof such olefins can range from 30 to 100%. Mixtures of these polymersare contemplated as part of the invention, as well. Other componentsthat typically can be included in such polyolefin compositions areamorphous polymers of C₃-C₂₀ olefins, whether used alone or asco-polymers of two different olefins or as terpolymers of threedifferent olefins. Such amorphous components are typically added toenhance the low temperature impact or paintability properties of thepolyolefin composition. For example, the polymer composition of U.S.Pat. Nos. 4,945,005, 4,997,720 and 5,498,671 can be used as thepolyolefin component in this invention.

The polyolefin compositions of the invention may include anythermoplastic polyolefin base component of one or more polyolefins thatdo not crosslink but that have compatibility with one or moreunsaturated polyolefins that are capable of crosslinking underirradiation, although the polyolefin base component is preferably apolyolefin, more preferably a blend of a crystalline or semi-crystallinepoly-α-olefin and an amorphous poly-α-olefin, and most preferably ablend of a semicrystalline propylene homopolymer or copolymer withanother poly-α-olefin and an amorphous copolymer or terpolymer ofethylene with another α-olefin or diene. Although any diene is suitablefor use in a co- or terpolymer, preferably the diene is ethylidinenorbornene, dicyclopentadiene, or hexadiene. The most preferredpolyolefin base component includes a semi-crystalline polypropyleneblended with an ethylene/α-olefin copolymer. The term“poly-α-olefins(s)” used in the invention means alkenes of 1 to 20carbon atoms, preferably 1 to 10 carbon atoms, having a double bondbetween the first and second carbon atoms. The polyolefin component is abase component, i.e., is the predominant component in the composition,and is not capable of crosslinking under the radiation described herein.This base component is typically present in an amount of about 99 to 55weight percent of the composition, preferably about 95 to 65 weightpercent of the composition, and more preferably about 90 to 70 weightpercent of the composition. The polyolefin component, or polyolefin basecomponent, is generally the remainder of the polyolefin compositionafter the radiation-crosslinkable component, photoinitiator and anyoptional filler are combined.

The polyolefin of the polyolefin base component is consideredsemi-crystalline when it has a crystallinity of at least about 30%,while fully crystalline materials, having a crystallinity of from 70 to100% as determined by X-ray diffraction, are also suitable. Whenpolypropylene is the selected olefin, a degree of crystallinity ofbetween 30 to 98% is acceptable to achieve sufficiently crystallinebehavior, although 60 to 70% is preferred, amorphous polyolefinstypically have a crystallinity of below 30%. The molecular weightaverage of the polyolefin is typically between 10,000 and 300,000, moretypically between 50,000 and 150,000. Blends of different molecularweight polymers may be utilized, if desired.

The enhanced surface durability polyolefin composition also includes aradiation-crosslinkable component and a photoinitiator. Theradiation-crosslinkable component is typically an unsaturatedpolyolefin. The unsaturated polyolefin may be any suitable polyolefindescribed herein for the polyolefin component, except that it shouldhave at least about one percent of its covalent bonds unsaturated. It ispreferred to have greater unsaturation in the radiation-crosslinkablecomponent, which results in greater and more rapid crosslinking whenexposed to radiation and ultimately enhances the surface characteristicsof the polyolefin composition to a greater extent. The unsaturatedpolyolefin may be, for example, an ethylene, propylene and dieneterpolymer; polybutadiene; polyisoprene; a styrenic polymer; amethacrylate grafted polybutadiene or a mixture thereof; or the like.Preferably, however, the radiation-crosslinkable component is anethylene/α-olefin copolymer, and more preferably an copolymer ofethylene and propylene. The radiation-crosslinkable component is presentin an amount sufficient to enhance the surface durability of thepolyolefin composition when radiation-cured. The radiation-crosslinkablecomponent is preferably present in about 1 to 30 weight percent, morepreferably about 5 to 20 weight percent, and most preferably about 10 to15 weight percent, of the polyolefin composition.

The term “methacrylate grafted polybutadiene” is known to those skilledin the art. According to this invention “methacrylate graftedpolybutadiene” encompasses polymers with methacrylate groups grafted topolybutadiene by any known method, for example coupling through freeradical reactions, through linking groups, and so on.

Methacrylate grafted polybutadiene may be prepared for example, by anymethod as described in U.S. Pat. Nos. 4,857,434, 3,957,903, 4,085,166,3,910,992 and 5,362,806, all incorporated herein by reference.Methacrylate grafted polybutadienes where the methacrylate groups aregrafted onto a maleated polybutadiene as described in U.S. Pat. Nos.4,857,434 and 5,362,806 are advantageously employed.

The preferred methacrylate grafted polybutadienes of this invention maysimply be composed of maleated polybutadiene and a functionalmethacrylate such as hydroxyethyl methacrylate or glycidyl methacrylate,such as described in U.S. Pat. Nos. 4,857,434 and 5,362,806. They mayfurther include other components as described in U.S. Pat. No.5,362,806.

Some of the preferred methacrylate grafted polybutadienes of thisinvention are commercially available, for instance the Ricacryl®methacrylated polybutadienes available from Ricon Resins, GrandJunction, Colo. Specific examples are Ricacryl® 131MA17 and Ricacryl®3500.

In addition to polybutadiene, other polymeric substrates may bemethacrylate grafted and employed as the radiation-crosslinkablecomponent according to this invention. Other suitable substrates formethacrylate grafting as described above are for example copolymers ofethylene, propylene and diene monomers.

Other examples of radiation crosslinkable components include glycidylethers of polyhydric alcohols such as those described in U.S. Pat. No.3,910,922, incorporated herein by reference.

Modifications to the crosslinkable component are possible such asincorporation of tetrafluoroethylene monomer or styrene monomer in thebackbone which may impart desirable properties other than sites forcrosslinking.

The polyolefin composition also includes a photoinitiator, or freeradical initiator, to facilitate curing of the polyolefin compositionwhen irradiated. The photoinitiator may include any compounds capable ofinitiating free radical cleavage to crosslink theradiation-crosslinkable component. Suitable photoinitiators typicallyinclude benzoin and benzoin ether derivatives; benzil ketal derivatives;α,α-dialkyoxyacetophenone derivatives; α-aminoalkylketone derivatives;α-hydroxyalkylketone derivatives; mono- or bis-acylphosphine oxides;mono- or bis-acylphosphine sulfides; phenylglyoxylate derivatives;O-acyl-2-oximino ketone derivatives; benzophenone and its derivatives;Michler's ketone and its derivatives; thioxanthone and its derivatives;and all the polymer-bound compounds of the type mentioned above, and thelike. Specific photoinitiators can include for example2,2-dimethoxy-2-phenylacetophenone,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide,2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 2methyl-1-(4-methylthiophenyl)-2-morpholine-propan-1-one and1-hydroxy-cyclohexylphenyl ketone. Preferred photoinitiators are of thetype—benzil ketal derivatives and acylphosphine oxides or a mixturethereof. The photoinitiator is typically present in an amount sufficientto initiate crosslinking of the radiation-crosslinkable component whenthe polyolefin composition is exposed to radiation. Preferably, thephotoinitiator is present in an amount of about 0.01 to 5 weightpercent, more preferably about 0.05 to 4 weight percent, and mostpreferably about 0.1 to 3 weight percent, of the polyolefin composition.As photoinitiators tend to be costly, it is also preferred to use theleast amount of photoinitiator necessary to cure the polyolefincomposition in a sufficiently rapid manner.

Fillers may optionally be included within the polyolefin compositions ofthe present invention. Calcium carbonate, clay, talc, mica,wollastonite, glass, silica, zinc oxide, titanium dioxide, and the likeare all suitable fillers for use with the polyolefins. The mostappropriate fillers are typically selected depending upon the desiredqualities in the final polyolefin products, and selecting such fillersis readily accomplished by one of ordinary skill in the art. The fillersare typically present in an amount of about 1 to 30 weight percent, andpreferably between 5 to 15 weight percent, of the polyolefincomposition.

To prepare the polyolefin composition, a polyolefin component, at leastone radiation-crosslinkable component, at least one photoinitiator, andany optional filler(s) are combined to form a curable composition. Thevarious components are typically mixed and the radiation-crosslinkablecomponent, photoinitiator, and polyolefin component are preferably,substantially uniformly dispersed.

The polyolefin composition can also include one or more stabilizers toimpart stability to the composition during mixing, during mechanicalprocessing and during the intended end use application which may includeexposure to elevated temperatures or exposure to sunlight or both. Thestabilizers of the instant invention may be selected from the following:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethophenol, nonylphenols which are linear orbranched in the side chains, for example, 2,6 di-nonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-di-dodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

1.4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol,δ-tocopherol and mixtures thereof (Vitamin E).

1.5. Hydroxylated thiodiphenyl ethers, for example2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis-(3,6-di-sec-amylphenol),4,4′-bis-(2,6-dimethyl-4-hydroxyphenyl) disulfide.

1.6. Alkylidenebisphenols, for example2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis(4,6di-tert-butylphenol), 2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4metholphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methyl-phenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-nodecylmercapto-butane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenol)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methyl-benzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O-, N- and S-benzyl compounds, for example3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxy-dibenzyl ether,octadecyl-4-hydroxy-3,5 dimethylbenzylmercaptoacetate,tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide,isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates, for exampledioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonate,di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate,di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate,bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Aromatic hydroxybenzyl compounds, for example1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine Compounds, for example2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenolpropionyl)-hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

1.11. Benzylphosphonates, for exampledimethyl-2,5-di-tert-butyl-4-hydroxybenzyl-phosphonate,diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate,dioctadecyl-5-tert-butyl-4-hydroxy3-methylbenzyl-phosphonate, thecalcium salt of the monoethyl ester of3,5-di-tert-butyl-4-hydroxybenzyl-phosphonic acid.

1.12. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol,ioctanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol, ethanol,noctanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol,ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethyleneglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.15. Esters of β-(3.5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3.5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono-or polyhydric alcohols, e.g. with methanol, ethanol, octanol,octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g.N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

1.18. Ascorbic acid or derivatives, for example, a salt or ester ofascorbic acid, such as ascorbyl palmitate, dipalmitate L-ascorbate,sodium L-ascorbate-2-sulfate, or an ascorbic salt, such as sodium,potassium, and calcium, or mixtures thereof.

1.19. Aminic antioxidants, for exampleN,N′-di-isopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octylated diphenylamine, for examplep,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, Bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyldiphenylamines, a mixture of mono- anddialkylated nonyldiphenylamines, a mixture of mono- and dialkylateddodecyldiphenylamines, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamines, a mixture of mono- and dialkylatedtert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylatedtert-octylphenothiazines, N-allylphenothiazin,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine,bis(2,2,6,6-tetramethylpiperid-4-yl)sebacate,2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

2. UV Absorbers and Light Stabilisers

2.1. 2-(2′-Hydroxyphenyl)benzotriazoles, for example2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chloro-benzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-(3′,5′-bis-(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole,mixture of2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)-carbonylethyl]-2′-hydroxyphenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole, and2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol];the transesterification product of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol300;, whereR=3′-tert-butyl4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl.

2.2.2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxyand 2′-hydroxy-4,4′-dimethoxy derivatives.

2.3. Esters of substituted and unsubstituted benzoic acids, as forexample 4-tertbutyl-phenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoyl resorcinol, bis(4-tert-butyl-benzoyl) resorcinol,benzoyl resorcinol, 2,4-di-tertbutylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methylα-cyano-β-methyl-p-methoxy-cinnamate, butylα-cyano-β-methyl-p-methoxy-cinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of2,2′-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or1:2 complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. themethyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonicacid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenylundecylketoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additionalligands.

2.6. Sterically hindered amines, for examplebis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(2,2,6,6-tetramethyl-4-piperidyl)succinate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate,bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate,the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperdine and succinicacid, the condensate ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dion,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, the condensate ofN,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensate of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis-(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6 tetramethyl-4-piperidyl)pyrrolidin-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, amixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, a condensation product of1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine aswell as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No.[136504-96-6]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimid,N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decane, areaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decaneand epichlorohydrin.

2.7. Oxamides, for example 4,4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide and mixtures of ortho- andpara-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxy-disubstituted oxanilides.

2.8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazine,2-(2-hydroxyphenyl)-4(4-methoxyphenyl)-6-phenyl-1,3,5-triazine.

3. Metal Deactivators, for example N,N′-diphenyloxamide,N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl) hydrazine,N,N′-bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)hydrazine,3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide,oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide,N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyldihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

4. Phosphites and Phosphonites, for example triphenyl phosphite,diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite,diisodecyloxy-pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl)pentacythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylenediphosphonite,6-isooctyloxy-2,4,8,10--tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin,bis(2,4-di-tert-butyl-6-methylphenyl)methylphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphite.

5. Hydroxylamines, for example, N,N-dibenzylhydroxylamnine,N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine,N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine,N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine,N-hexadecyl-N-octadecylhydroxylamine,N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derivedfrom hydrogenated tallow amine.

6. Nitrones, for example, N-benzyl-alpha-phenyl-nitrone,N-ethyl-alpha-methyl-nitrone, N-octyl-alpha-heptyl-nitrone,N-lauryl-alpha-undecyl-nitrone, N-tetradecyl-alpha-tridecylnitrone,N-hexadecyl-alpha-pentadecyl-nitrone,N-octadecyl-alpha-heptadecyl-nitrone,N-hexadecyl-alpha-heptadecyl-nitrone,N-ocatadecyl-alpha-pentadecyl-nitrone,N-heptadecylalpha-heptadecyl-nitrone,N-octadecyl-alpha-hexadecyl-nitrone, nitrone derived fromN,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

7. Thiosynergists, for example, dilauryl thiodipropionate or distearylthiodipropionate.

8. Peroxide Scavengers, for example esters of β-thiodipropionic acid,for example the lauryl, stearyl, myristyl or tridecyl esters,mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zincdibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritoltetrakis(β-dodecylmercapto)propionate.

9. Basic Co-stabilisers, for example, melamine, polyvinylpyrrolidone,dicyandiamide, triallyl cyanurate, urea derivatives, hydrazinederivatives, amines, polyamides, polyurethanes, alkali metal salts andalkaline earth metal salts of higher fatty acids for example calciumstearate, zinc stearate, magnesium behenate, magnesium stearate, sodiumricinoleate and potassium palmitate, antimony pyrocatecholate or tinpyrocatecholate.

10. Other Additives, for example, plasticisers, lubricants, emulsifiers,pigments, rheology additives, catalysts, flow-control agents, opticalbrighteners, flameproofing agents, antistatic agents and blowing agents.

11. Benzofuranones and Indolinones, for example those disclosed in U.S.Pat. No. 4,325,863, U.S. Pat. No. 4,338,244, U.S. Pat. No. 5,175,312,U.S. Pat. No. 5,216,052, U.S. Pat. No. 5,252,643, DE-A4316611,DE-A-4316622, DE-A4316876, EP-A-0589839 or EP-A0591102 or 3-[4-(2acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one,5,7-di-tert-butyl-3-[4-(2 stearoyloxyethoxy)phenyl]benzofuran-2-one,3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one],5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one,3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

The concentration of the costabilizer in the thermoplastic polyolefincomposition is usually from 0.1 to 5 percent by weight of thecomposition.

The polyolefin composition is then preferably formed into a desiredproduct by a variety of conventional means, such as injection molding,coinjection molding, blow molding, extrusion, and the like. One ofordinary skill in the art can envision a broad array of useful, desiredproducts easily manufactured by the present invention, includingelectrical components such as electrode manufacture or insulation,surface treatment of a variety of materials, and automotive parts. Avariety of applications may be useful just in the automotive field,although they apply to a variety of other fields of endeavor. It isclear that interior and exterior automotive applications such asinstrument panels, thermoformed skins, bumper fascia, claddings, andother interior and exterior trim components can be readily produced withsuperior durability due to the present invention.

The polyolefin composition in its uncured state is cured by subjectingthe composition to irradiation. The radiation-crosslinkable componentcrosslinking is initiated by a source of ionizing radiation capable ofproducing free radicals, such as gamma, UV, electron beam, visible,microwave, or infrared radiation. More than one type of radiation may beused, although this is typically avoided due to cost considerations.Preferably, UV or electron beam radiation is used for the curingprocess.

For example, when UV radiation is used as the radiation source, thecuring process requires at least one UV lamp that directs UV light ontothe formulated product. These UV lamps may provide either arc light,which includes a medium pressure mercury lamp and a high pressure xenonlamp, or laser light. The photoinitiator(s) used must have an absorptionspectra that at least partially overlaps with the emission spectra ofthe UV lamp, such that the photoinitiator is capable of absorbing the UVenergy. The photoinitiator rapidly initiates a chemical reaction thatquickly converts the resin, or radiation-crosslinkable component, into acured (crosslinked) form. This photoinitiated curing typically occurs inless than one second, although this will depend on the rate of UV energytransfer. The Uv energy preferably has a wavelength of between about 300to 400 nm. The radiation source typically provides energy at a rate ofabout 2-15 J/cm². For example, a lamp of about 1-6 J/cm² would typicallytake less than one second to cure a thermoplastic polyolefincomposition. It of course is possible for other cure mechanisms (such asthermal or moisture induced curing) to continue well afterphotoinitiated crosslinking is complete.

A test was developed by Solvay Engineered Polymers to measure relativesurface scratch resistance. For this test, the test specimens are atleast 4″×4″ (100 mm×100 mm ) in dimensions, with a hole drilled in themiddle for mounting. A Taber Abrasion test machine (described further inASTM D1044) was modified by substituting a stainless steel slider with asharp tip (radius ca. 0.25 mm) in place of the sanding wheels to scratchthe surface of the specimens. With the tip offset 34 mm from the centerof rotation and the turntable spinning at 72 rpm, the actual slidingvelocity is equal to 25 mm/sec, which is similar to the condition ofsomeone scratching a surface at normal speed with a fingernail. The testis terminated after one single revolution. The normal load used for thistest is 1 lb. Upon completion of the test, the specimens are then ratedvisually on a numerical scale of 1 to 5 (1=excellent, hardly any marringis visible; 5=badly scratched). The width of the wear track and thecharacteristics of the failure surface can also be further studied withan optical microscope or more sophisticated instruments such as surfaceprofilometer and scanning force microscope. The typical dimensions ofthe wear paths corresponding to the mar ratings are as follows.

Mar Rating Width of Scratch (μm) Relative Performance 1 <50 Excellent1.5  50-200 Very good 2 200-300 Good 3 300-400 Fair 4 400-500 Bad 5 >500Poor

A value of1.5 or less in this test is indicative of very good orexcellent performance.

EXAMPLES

The invention is further defined by reference to the following examplesdescribing in detail the preparation of the compositions of the presentinvention. It will be apparent to those of ordinary skill in the artthat many modifications, both to materials and methods, may be practicedwithout departing from the purpose and intent of this invention.

Photoinitiator A is 2,2-dimethoxy-2-phenylacetophenone andphotoinitiator B is 2-methyl-1-[4-methylthio)phenyl]-2-morpholinopropane-1-one.

Examples 1-2 UV Irradiation with and without Photoinitiator

Examples 1-2, set forth in Table I below, compare samples of polyolefincomponent and radiation-curable component both with and without aphotoinitiator that were subjected to UV radiation by a mercury lamp.The formula with photoinitiator showed significant increase in Shorehardness upon irradiation, whereas the formula without photoinitiatorshowed no change in Shore hardness. After soaking both formulations inxylene for four hours, the sample with photoinitiator also showed lessweight increase, indicating there was crosslinking on the surface thatwas slowing down the diffusion of xylene into the 5 sample plaque. Thefeasibility of the UV curing process is thus confirmed.

TABLE I Indication of Crosslinking via UV-Curing Compositions (wt %)Example 1 (Control) Example 2 Polypropylene¹ 30 28.8 Polybutadiene² 69.867 Photoinitiator A 0 4 Antioxidant³ 0.2 0.2 Irradiation Source MercuryLamp (H bulb) Mercury Lamp (H bulb) Atmosphere Nitrogen NitrogenIrradiation Level 2 and 4 J/cm² 2 and 4 J/cm² Shore “A” (0 J/cm²) 87 86(2 J/cm²) 88 89 (4 J/cm²) 90 95 Shore “D” (0 J/cm²) 25 21 (2 J/cm²) 2426 Wt. Increase after 4-hr Xylene Soak (2 J/cm²) 104% 89% (4 J/cm²)  96%59% ¹isotactic polypropylene, M_(w) = 240,000; M_(w)/M_(n) = 4.1;²amorphous cis-1,4 polybutadiene, Mooney Viscosity ML (1 + 4, 100 C) =40. ³antioxidant = 1:1 tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)]methane/tris(2,4-di-tert)butylphenyl)phosphite

Examples 3-5 Surface Characteristics Based on Photoinitiation

Examples 3-5, set forth in Table II below, compared the surface hardnessand mar resistance performance of representative engineered polyolefinblends before and after photoinitiation. In this experiment, a mercury“D” bulb was used as a radiation source. This bulb has lower emissionsat short wavelengths and enhanced emissions at longer wavelengths whencompared to the mercury “H” bulb. Examples 4 and 5, using photoinitiator“A” and photoinitiator “B” respectively, exhibited significantly biggerincreases in hardness and much improved mar resistance than the samplewithout photoinitiator in Example 3.

TABLE II Improvement of Surface Durability through a Mercury LampUV-Curing Process Ex. 3 Compositions (wt %) (control) Example 4 Example5 Polypropylene¹ 69.8 67.8 67.8 Poly(ethylene-co-α-olefin)² 15 15 15Methacrylate grafted 15 15 15 polybutadiene³ Photoinitiator A 0 2 0Photoinitiator B 0 0 2 Antioxidant⁴ 0.2 0.2 0.2 Irradiation SourceMercury Lamp with “D” Bulb Atmosphere Air Irradiation Energy Two levels:2.7 and 5.5 J/cm² Test Results after UV-cure: Shore “D” (0 J/cm²) 66 6565 (2.7 J/cm²) 67 68 69 (5.5 J/cm²) 67 69 70 Rockwell “R” (0 J/cm²) 7268 68 (2.7 J/cm²) 72 73 76 (5.5 J/cm²) 73 75 80 Scratch Rating (SolvayTest*) (0 J/cm²) 3.5 3.5 3.5 (2.7 J/cm²) 2.5 2.5 3.0 (5.5 J/cm²) 3.0 1.52.0 ¹isotactic polypropylene, M_(w) = 240,000; M_(w)/M_(n) = 4.1;²poly(ethylene-co-octene); M_(w) = 100,000; M_(w)/M_(n) = 2;³methacrylate grafted polybutadiene, RICACRYL 3500. CAS #168612-08-6,available from Ricon Resins, Inc. ⁴antioxidant = 1:1tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)]methane/tris(2,4-di-tert-butylphenyl)phosphite.

Examples 6-9 Radiation-curable Components Having Greater Unsaturation

Examples 6-9, set forth in Table III below, were prepared such that theradiation-crosslinkable had higher unsaturation (moremethacrylate-grafted polybutadiene) when compounded and compared withthe formulations in Table II (Examples 3-5). The mar resistance ofExamples 6-9 after UV curing show further improvement in mar resistanceover the polyolefin composition with less unsaturation in theradiation-crosslinkable component.

TABLE III Surface Modification with Photoinitiators and UV-CuringComposition (wt %) Ex. 6 Ex. 7 Ex. 8 Ex. 9 Polypropylene¹ 67.8 67.8 67.867.8 Poly(ethylene-co-α-olefin)² 15 10 15 10 Methacrylate grafted 15 2015 20 polybutadiene³ Photoinitiator A 2 2 0 0 Photoinitiator B 0 0 2 2Antioxidant⁴ 0.2 0.2 0.2 0.2 Irradiation Source Mercury Lamp with “D”Bulb Atmosphere Air Irradiation Energy Two levels: 2.7 and 5.5 J/cm²Test Results after UV-cure: Shore “D” (0 J/cm²) 65 65 65 65 (2.7 J/cm²)68 68 69 67 (5.5 J/cm²) 69 69 70 68 Rockwell “R” (0 J/cm²) 69 64 68 62(2.7 J/cm²) 73 76 76 77 (5.5 J/cm²) 75 79 80 80 Scratch Rating (Solvay)(0 J/cm²) 3.5 4.0 3.5 4.0 (2.7 J/cm²) 2.5 2.0 4.0 2.5 (5.5 J/cm²) 1.51.5 2.0 1.5 ¹isotactic polypropylene. M_(w) = 240,000; M_(w)/M_(n) =4.1; ²poly(ethylene-co-octene); M_(w) = 100,000; M_(w)/M_(n) = 2;³methacrylate grafted polybutadiene, RICACRYL 3500, CAS #168612-08-6.Available from Ricon Resins, Inc. ⁴antioxidant = 1:1tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)]methane/tris(2,4-di-tert-butylphenyl)phosphite.

Example 10 UV Radiation & Thermal Treatment on Surface Durability

Example 10, set forth in Table IV below, was prepared to examine theeffect of treating the plastic component with UV radiation followed by athermal cure. The formulation when exposed to UV radiation and asubsequent thermal treatment resulted in a surface with improved marresistance compared with a plastic component which was exposed to thesame UV radiation but without the thermal cure.

TABLE IV Effect of UV Radiation and Thermal Curing Composition (wt %)Ex. 10 Polypropylene¹ 68.4 Methacrylate grafted 29.4 polybutadiene²Photoinitiator B 2.0 Antioxidant³ 0.2 Irradiation Source Mercury Lampwith “D” Bulb Atmosphere Air Irradiation Energy 10.8 J/cm² Thermal Cure80° C./2 hours Test Results after UV-cure: Scratch Rating (Solvay) (0J/cm²) 5.0 (10.8 J/cm²) 1.5 (10.8 J/cm² + 80° C./2 hours) 1.0 Note:¹isotactic polypropylene, M_(w) = 240,000; M_(w)/M_(n) = 4.1;²methacrylate grafted polybutadiene, RICACRYL 3500, CAS #168612-08-6,available from Ricon Resins, Inc. ³antioxidant = 1:1 tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)] methane/tris(2,4-di-tert-butylphenyl) phosphite.

Example 11 Incorporation of Stabilizers

Articles prepared according to Example 10 which additionally contain ahindered amine with a molar mass less than 2000, preferably a hinderedamine with a molecular weight between 400-1000, a hindered amine with amolar mass greater than 2000, preferably a hindered amine with amolecular weight between 2000-4000, a UV absorber of the hydroxyphenylbenzotriazole class or mixtures thereof, exhibit improved mar resistanceand stability against the deleterious effects of UV light and thermalexposure.

Although preferred embodiments of the invention have been described inthe foregoing description, it will be understood that the invention isnot limited to the specific embodiments disclosed herein but is capableof numerous modifications by one of ordinary skill in the art. It willbe understood that the materials used and the chemical details may beslightly different or modified without departing from the methods andcompositions disclosed and taught by the present invention.

What is claimed is:
 1. A thermoplastic polyolefin composition havingenhanced surface durability comprising a blend of: a base component of athermoplastic polyolefin; at least one radiation-crosslinkable componentwhich comprises a methacrylate grafted polybutadiene, present in anamount sufficient to enhance the surface durability of the thermoplasticpolyolefin component when radiation-cured; and at least onephotoinitiator present in an amount sufficient to initiate crosslinkingof the radiation-crosslinkable component.
 2. A composition according toclaim 1 which further comprises a filter.
 3. A composition according toclaim 2 wherein the filler is calcium carbonate, clay, talc, mica,glass, zinc oxide, titanium dioxide, wollastonite, silica, or a mixturethereof.
 4. A composition according to claim 1 wherein the thermoplasticpolyolefin base component is present in an amount of about 99 to 55weight percent of the composition.
 5. A composition according to claim 4wherein the thermoplastic polyolefin base component is present in anamount of about 95 to 65 weight percent of the composition.
 6. Acomposition according to claim 1 wherein the radiation-crosslinkablecomponent is present in an amount of about 1 to 30 percent by weight ofthe thermoplastic polyolefin composition.
 7. A composition according toclaim 1 wherein the photoinitiator is benzoin, a benzoin ether compound,a benzil ketal compound, an α,α-dialkyloxy acetophenone compound, anα-aminoalkylphenone compound, an α-hydroxyalkylphenone compound, anacylphosphine oxide, an acylphosphine sulfide, a phenylglyoxylatecompound, an O-acyl-2-oximino ketone compound, a benzophenone compound,a Michler's ketone compound, a thioxanthone compound, a polymer-boundcompound of a previously recited photoinitiator, or a mixture thereof.8. A composition according to claim 7 wherein the photoinitiator is abenzil ketal compound or an acylphosphine oxide.
 9. A compositionaccording to claim 1 wherein the photoinitiator is present in an amountof about 0.01 to 5 percent by weight of the composition.
 10. Acomposition according to claim 1 wherein the radiation-crosslinkablecomponent is cross-linked to provide enhanced surface durability with anouter surface of the composition containing a sufficient amount of thecross-linked component to provide a scratch rating of 2 or lower on theSolvay scale.
 11. A composition according to claim 1 which additionallycontains at least one stabilizer selected from the group consisting ofphenolic antioxidants, phosphites, hydroxylamines, hindered amines, UVabsorbers and combinations thereof.
 12. A method of providing a curedthermoplastic polyolefin composition having enhanced surface durabilitywhich comprises: preparing a mixture comprising thermoplastic polyolefinbase component, at least one radiation cross-linkable component whichcomprises a methacrylate grafted polybutadine in an amount sufficient toenhance the surface durability of the base component when radiationcured; and at least one photoinitiator in an amount sufficient tofacilitate crosslinking of the radiation crosslinkable component whenthe thermoplastic polyolefin composition is exposed to radiation; andexposing a surface of the thermoplastic polyolefin composition toradiation in an amount sufficient to crosslink theradiation-crosslinkable component at least at the exposed surface,thereby providing a thermoplastic polyolefin composition having enhancedsurface durability.
 13. A method according to claim 12 wherein theradiation is selected to be ultraviolet, electron beam, gamma, visible,microwave, infrared or thermal radiation, or mixtures thereof.
 14. Amethod according to claim 12 wherein the radiation is imparted at apower of 0.1 J/cm² and above and at a wavelength between 200 and 500 nm.15. A method according to claim 12 which further comprises forming thethermoplastic polyolefin composition into a desired shape prior toexposing the surface of the composition to the radiation.
 16. A methodaccording to claim 12 wherein the composition additionally contains atleast one stabilizer selected from the group consisting of phenolicantioxidants, phosphites, hydroxylamines, hindered amines, UV absorbersand combinations thereof.
 17. A thermoplastic polyolefin compositionhaving enhanced surface durability which is formed by a method whichcomprises: preparing a mixture comprising thermoplastic polyolefin basecomponent, at least one radiation cross-linkable component whichcomprises a methacrylate grafted polybutadine in an amount sufficient toenhance the surface durability of the base component when radiationcured; and at least one photoinitiator in an amount sufficient tofacilitate crosslinking of the radiation crosslinkable component whenthe thermoplastic polyolefin composition is exposed to radiation; andexposing a surface of the thermoplastic polyolefin composition toradiation in an amount sufficient to crosslink theradiation-crosslinkable component at least at the exposed surface,thereby providing a thermoplastic polyolefin composition having enhancedsurface durability.
 18. A thermoplastic polyolefin molded article whichwill have enhanced surface durability when a surface of the article isexposed to radiation, comprising a blend of: a base component of athermoplastic polyolefin; at least one radiation-crosslinkable componentselected from the group consisting of ethylene/propylene/dienecopolymer, polybutadiene, methacrylate grafted polybutadiene,polyisoprene, and mixture thereof, present in an amount sufficient toenhance surface durability of the thermoplastic polyolefin componentwhen radiation-cured; and at least one photoinitiator present in anamount sufficient to initiate crosslinking of theradiation-crosslinkable component.
 19. A molded article according toclaim 18 which further comprises a filler.
 20. A molded articleaccording to claim 19 wherein the filler is calcium carbonate, clay,talc, mica, glass, zinc oxide, titanium dioxide, wollastonite, silica,or a mixture thereof.
 21. A molded article according to claim 18 whereinthe radiation-crosslinkable component is present in an amount of about 1to 30 percent by weight of the thermoplastic polyolefin composition. 22.A molded article according to claim 18 wherein the photoinitiator isbenzoin, a benzoin ether compound, a benzil ketal compound, anα,α-dialkyloxy acetophenone compound, an α-aminoalkylphenone compound,an α-hydroxyalkylphenone compound, an acylphosphine oxide, anacylphosphine sulfide, a phenylglyoxylate compound, an O-acyl-2-oximinoketone compound, a benzophenone compound, a Michler's ketone compound, athioxanthone compound, a polymer-bound compound of a previously recitedphotoinitiator, or a mixture thereof.
 23. A molded article according toclaim 22 wherein the photoinitiator is a benzil ketal compound or anacylphosphine oxide.
 24. A molded article according to claim 18 whereinthe photoinitiator is present in an amount of about 0.01 to 5 percent byweight of the molded article.
 25. A molded article according to claim18, which when exposed to radiation, will have enhanced surfacedurability as measured by having a scratch rating of 2 or lower on theSolvay scale.
 26. A molded article according to claim 18 whichadditionally contains at least one stabilizer selected from the groupconsisting of phenolic antioxidants, phosiphites, hydroxylamines,hindered amines, UV absorbers and combinations thereof.
 27. A moldedarticle according to claim 18 which has been exposed to radiation.